UEFA has announced it will be investigating Premier League champions Manchester City for potential breaches of Financial Fair Play regulations.
The probe has been launched following a series of allegations made by media outlets, including German magazine Der Spiegel.
A UEFA statement said: "The Investigatory Chamber of the independent UEFA Club Financial Control Body has today opened a formal investigation into Manchester City FC for potential breaches of Financial Fair Play (FFP) regulations.
"The investigation will focus on several alleged violations of FFP that were recently made public in various media outlets.
"UEFA will make no further comments on the matter while the investigation is ongoing."
Der Spiegel has made a series of allegations over the last few months based on leaked emails between club officials suggesting that City had attempted to circumvent UEFA's FFP regulations, and most recently, that they had broken transfer rules with the signing of Argentinian midfielder Bruno Zuculini in 2014.
The club have previously responded to each allegation with the same statement, which said: "We will not be providing any comment on out of context materials purported to have been hacked or stolen from City Football Group and Manchester City personnel and associated people.
"The attempt to damage the Club's reputation is organized and clear."
City's response on this occasion was swift and robust, insisting that the allegations were "entirely false" and welcoming the investigation.
A statement on the club's official website, www.mancity.com, said: "Manchester City welcomes the opening of a formal UEFA investigation as an opportunity to bring to an end the speculation resulting from the illegal hacking and out of context publication of City emails.
"The accusation of financial irregularities are entirely false. The club's published accounts are full and complete and a matter of legal and regulatory record."
Possible Champions League exclusion
Earlier in the year UEFA's chief FFP investigator Yves Leterme claimed that City could be excluded from the Champions League if they are found to have deceived UEFA over their income from a series of lucrative sponsorship deals.
Leterme told Sport and Strategy magazine: "If what has been written about Manchester City is true, there might be a serious problem.
"This can lead to the heaviest punishment - exclusion from UEFA competitions."
Leterme's comments came after Der Spiegel alleged that only £8 million of the club's £67.5 million sponsorship deal with Etihad in 2015 came from the airline, with the rest coming from City owner Sheikh Mansour via his Abu Dhabi United Group.
World governing body FIFA also confirmed in November last year that it was looking into claims made in Danish newspaper Politiken that City were recruiting African players for free through FC Nordsjaelland's Right to Dream programme under an agreement between the two clubs.
However, FC Nordsjaelland president Tom Vernon told Politiken the club were "in compliance with all relevant football regulations".
Latest Sporting Life FC quiz
Fast Results
Scores
